Portland State University's Digital Repository, PDXScholar, preserves the University's research, unique resources, and other scholarly output with the goal of providng persistent, open access to that work.

Provides international transportation research. TRID combines records from TRB's Transportation Research Information Services (TRIS) database and the OECD's Joint Transport Research Centre's International Transport Research Documentation (ITRD) database. Covers the 1960's to the present.